I’ve never admitted that I do this to anyone because I felt embarrassed or thought maybe its something that people do sometimes when theyre alone. I bite the skin around my nails and eat it, not to the point where they bleed or are significantly damaged. It is the same with my calloused feet skin. I also eat my finger nails when i bite them and the inside of the skin on my lip. Ive been doing this for a long time i think (i remember the skin around my nails as far back as elementary school) I also used to eat paper and eraser heads occasionally when I was younger (again not to the point where it harmed me) just look for some insight, anything helps!